svn commit: r193193 - user/kmacy/releng_7_2_fcs/sys/sys
Kip Macy
kmacy at FreeBSD.org
Mon Jun 1 01:42:56 UTC 2009
Author: kmacy
Date: Mon Jun 1 01:42:56 2009
New Revision: 193193
URL: http://svn.freebsd.org/changeset/base/193193
Log:
remove gratuitous memory barriers
Modified:
user/kmacy/releng_7_2_fcs/sys/sys/buf_ring.h
Modified: user/kmacy/releng_7_2_fcs/sys/sys/buf_ring.h
==============================================================================
--- user/kmacy/releng_7_2_fcs/sys/sys/buf_ring.h Mon Jun 1 01:02:30 2009 (r193192)
+++ user/kmacy/releng_7_2_fcs/sys/sys/buf_ring.h Mon Jun 1 01:42:56 2009 (r193193)
@@ -117,7 +117,6 @@ buf_ring_enqueue(struct buf_ring *br, vo
while (br->br_prod_tail != prod_head)
cpu_spinwait();
br->br_prod_tail = prod_next;
- mb();
critical_exit();
return (0);
}
@@ -154,7 +153,7 @@ buf_ring_dequeue_mc(struct buf_ring *br)
#ifdef DEBUG_BUFRING
br->br_ring[cons_head] = NULL;
#endif
- mb();
+ rmb();
/*
* If there are other dequeues in progress
@@ -165,7 +164,6 @@ buf_ring_dequeue_mc(struct buf_ring *br)
cpu_spinwait();
br->br_cons_tail = cons_next;
- mb();
critical_exit();
return (buf);
@@ -196,7 +194,6 @@ buf_ring_dequeue_sc(struct buf_ring *br)
br->br_cons_head = cons_next;
buf = br->br_ring[cons_head];
- mb();
#ifdef DEBUG_BUFRING
br->br_ring[cons_head] = NULL;
@@ -207,7 +204,6 @@ buf_ring_dequeue_sc(struct buf_ring *br)
br->br_cons_tail, cons_head);
#endif
br->br_cons_tail = cons_next;
- mb();
critical_exit();
return (buf);
}
@@ -225,7 +221,7 @@ buf_ring_peek(struct buf_ring *br)
if ((br->br_lock != NULL) && !mtx_owned(br->br_lock))
panic("lock not held on single consumer dequeue");
#endif
- mb();
+ wmb();
if (br->br_cons_head == br->br_prod_tail)
return (NULL);
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